藻場のブルーカーボンの現在と課題

Greg Nishihara

長崎大学海洋未来イノベーション機構

藻場のブルーカーボンの現在と課題

Greg Nishihara

長崎大学海洋未来イノベーション機構

スライドの操作について

ショートカットキー	操作
?	スライド操作表
左キー	前のスライドへ移動
右キー	次のスライドへ移動
E	PDF出力モード
S	発表者モード
M	操作メニュー

スライドのファイルサイズは >45MB です。

https://gnishihara.github.io/oicn20221111/

What is Blue Carbon?

Brief history of climate change

1827 Jean-Baptiste Joseph Fourier establishes the framework for planetary energy balance (Fourier 1824, 1827)
1859 John Tyndall discovers that CO₂ is opaque to infrared light (Tyndall 1861)
1896 Svante Arrhenius calculates the effects of anthropogenic CO₂ on global warming (Arrhenius 1896)

フーリエは太陽光に熱せられた地表が赤外光を射出して、宇宙空間に熱を運んでいると提案し、大気が熱放射の一部を閉じ込めていることも提案した。
ティンダルは大気に存在する二酸化炭素と水蒸気は赤外光に不透明だと発見した。
アレニウスは化石燃料の燃焼と大気中の二酸化炭素の関係を発見し、人間活動によって地球温暖化が起きると提案した。
それにしても、その後（1900 – 1940）の誤った研究成果によって、二酸化炭素の温室効果は水蒸気よりも低いと考えられるようになった。

スペンサー・R・ワート「温暖化の<発見>とは何か」を参考にしました。 The first half of this slide deck is based on The Discovery of Global Warming (ISBN-13: 978-0674031890) by Spencer Weart, and the website that complements the work. https://history.aip.org/climate/index.htm#contents

First evidence of global warming

1930 - 1950: First evidence of warming (e.g., Callendar 1938)
From 1890 to 1935 mean global temperature increased by 0.5°C

Temperature variation from 1901 to 1930.

Fossil fuels drive CO₂ increase

1955 Hans Suess shows that fossil carbon is appearing in the atmosphere (Suess 1955).
1957 Roger Revelle showed that the complex chemistry of the oceans reduced the ideal amount of CO₂ that could be absorbed (Revelle and Suess 1957).

CO₂ added by fossil fuels (Revelle and Suess 1957).

Keeling’s curve

1960 First evidence that CO₂ concentrations in the atmosphere are increasing (Charles D. Keeling 1960).
Establishes the Mauna Loa CO₂ observations in 1958.

Mauna Loa Observatory, Hawaii (Keeling C. D. et al. 2001).

1970 代になると、温室効果に関する現象は重要な研究問題となっていた
それにしても、地球の平均温度に二酸化炭素の影響は疑われていました。
その主な理由は当時に起きていた大気汚染（すす）でした。汚染物質は地表にとどく太陽光を減らす効果があり、その結果地球の平均温度も下げる効果があった。
どうじに、メタンや二酸化窒素などのガスが、温室効果ガスとして認識されるようになる。
ちょうどこの時期、ハワイのマウナロア火山にキーリングが二酸化炭素のモニタリング基地を設置する。
図には1800年代の二酸化炭素濃度と1960年から計測している二酸化炭素濃度の変動を示している。
データの細かな上下運動は地球における光合成による二酸化炭素濃度の季節消長です。

Global Cooling ?

1961 Global cooling was occurring since 1940 (Mitchell 1961).
Many agencies, including the Japan Meteorological Agency (JMA) reported cooling in the 1970s
Dust and soot (particulates) from industrial pollution contributed to temporary cooling of the Northern Hemisphere, but no cooling was observable in the Southern Hemisphere.

Hansen, Wigley, and Jones

The effects of CO₂ may not be detectable until around the turn of the century (Wigley and Jones 1981).

Detecting CO₂-induced climatic change (Wigley and Jones 1981).

J. Hansen et al. (1981) also explains that the effects of increasing atmospheric CO₂ will be clear by the 21st century. Jones, Wigley, and Wright (1986) also demonstrated global warming from 1861 to 1984.

Final adjustments

Heat island effects of cities were removed from the temperature record.
Measurements of microwave radiation to measure the temperature of the middle heights of the atmosphere suggested cooling(National Research Council 2000), but were later discredited (Santer et al. 2003).
1990s showed a drop in global temperatures, which was attributed to the 1991 Pinatubo volcanic eruption (James Hansen et al. 1992).

Indirect evidence

Unfolding of leaves advanced by 6 days, leaf coloring delayed by 5 days, average growing increased by 11 days (Menzel and Fabian 1999).
Seasonal decrease in CO₂ due to photosynthesis was occurring earlier, by almost one week (C. D. Keeling, Chin, and Whorf 1996).
Minimum temperatures increasing twice as fast as maximum temperatures, precipitation is increasing, atmospheric water vapor is increasing, extreme hydrological events are increasing (Easterling et al. 2000).

Hockey stick

1999 The famous hockey-stick figure of global temperatures (Mann, Bradley, and Hughes 1999) that was also featured in the 2001 IPCC report on climate change.

The oceans are warming

The heat content of the oceans (Levitus et al. 2000).

Heat content of the oceans increased by 2 × 10²³ J between 1950 to 1990, upper 300m increased by 0.31°C (Levitus et al. 2000).

The heat content of the oceans is the best measure of global temperature change.

What is Blue Carbon?

Blue Carbon is carbon that is stored in coastal and marine ecosystems.

The greenhouse effect

Greenhouse effect mechanism

The total energy budget of the earth is dominated by solar energy.
However, 30% of solar energy is reflected into space.
Solar energy reaching the earth surface is absorbed and re-radiated as infrared radiation.
Infrared radiation is released into the atmosphere and some escapes into space.
Greenhouse gases in the atmosphere absorb and emits infrared radiation, which leads to warming.

Greenhouse gases

Four major components

Water vapor (35 ~ 72%)
Carbon dioxide (9 ~ 26%)
Methane (4 ~ 9%)
Ozone (3 ~ 7%)

Other components

Nitrous oxide (N₂O), perfluorocarbons (PFC), chlorofluorocarbons (CFC), hydrofluorocarbons (HFC), sulfur hexafluoride (SF₆)

Global warming potential (GWP)

Gas	Lifetime (years)	100-year GWP
CO₂	1000s	1
CH₄	11.8	21 ~ 40
N₂O	109	265 ~ 310
PFC	52	6630 ~ 7380
CFC	52	4660 ~ 6226
HFC-134a	14	1300 ~ 1526
HFC-23	222	12400 ~ 14800
SF₆	3200	22800 ~ 23500

Carbon sinks and flows

Definition

Carbon sink: A process, activity, or mechanism that removes a greenhouse gas, aerosol, or a precursor from the atmosphere.

Carbon source: A process, activity, or mechanism that releases a greenhouse gas, aerosol, or a precursor into the atmosphere.

Major carbon sources and sinks

Fossil fuel emissions
Steel and cement production
Land use change
- Burning of grasslands and forests
- De-forestation
- Land-reclamation

Fossil fuels contribute the most carbon

Y2020 emissions

Coal 40%
Oil 32%
Gas 21%
Cement 5%

Carbon fluxes in the ecosystem

Seaweed POC and DOC includes alginates, xylans, and sulphated polysaccharides that resist microbial decomposition　(Trevathan-Tackett et al. 2015; Pedersen et al. 2021).

eDNA of seaweeds have been found in marine sediments and in 2000 year-old sediments (Zaborska et al. 2018; Ortega et al. 2019; Ortega, Geraldi, and Duarte 2020; Frigstad et al. 2021).

大気と海の二酸化炭素は海面で出たり入ったりします。この二酸化炭素交換量（二酸化炭素フラックス）は大気中と表面海水中の二酸化炭素分圧の差とガス交換係数の積で求められます。
二酸化炭素が海に溶け込むと、灰色でしめしたように平衡状態となります。
藻類は海水中に溶け込んだ二酸化炭素と重炭酸イオン吸収して光合成によって淡水化合物を生成します。
藻類が生成した淡水化合物の一部は溶存有機炭素と粒子有機炭素として海水中に流出します。
よるになると、海藻は呼吸して、二酸化炭素を海水中に放出します。
緑色でハイライト部分が光合成の反応式を簡易にあらわしています。
上の式は二酸化炭素を吸収したときの反応式。
下の式はCCMにおける反応式です。CAは carbonic anhydrase、つまり炭酸脱水酵素です。
当然、光合成と呼吸をすることで、藻類は酸素を排出したり吸収したりもします。
さらに黄色でしめした機構も働いています。これは藻類における石灰化の機構です。
多くの藻類は石灰を形成して体の構造に組み込んでいます。
ところが 1 モルの炭酸カルシウムに対して、1 モルの二酸化炭素が排出される。
それにしても、排出された二酸化炭素は光合成によって利用されるとも考えられる。
ここまでは藻類中心の流れです。ところが、藻類が生成した有機炭素は食物連鎖に輸出されます。
近くに沈殿しなかった炭素カルシウムは外洋に輸出されます。十分に深い場所であれば、沈殿した炭酸カルシウムは再び溶解されます。
それにしても一部の炭酸カルシウムは海底まで沈殿して、底質に埋没されます。
有機炭素については、食物連鎖に入って代謝されます。
一部のの炭素は二酸化炭素として呼吸されますが、残りは動物や微生物のバイオマスとして一時的に貯蔵されます。
このように、7Gt以上の炭素は海洋動物に貯蔵されているとも考えられています。
このシステムの中で、酸素、二酸化炭素、有機炭素のフラックスは未だに不明です。
さらに、食物連鎖にどの程度炭素が貯蔵されているのか、移動しているのかは不明です。
とくに、微生物と寿命の短い整備つの役割は活発に議論されています。

Ecosystem perspective

私の研究室が検討している仮説を紹介ます。
いそやけと言う現象が世界的に問題になっています。沿岸生態系から海藻群落、藻場、が損失ことをいそやけというっています。
九州の場合、いそやけの原因は藻食性生物の過剰なせつじあつが問題です。この問題は食害と呼ばれています。
藻食性生物が多いとき、食害が高くなり、海藻が減ります。
海藻が少なくなると、生態系の光合成活動が減り、生態系の炭素固定能も減少します。
ところが、藻食性生物を制御することができれば、海藻が増えます。
よって、生態系の光合成活動が増加して、炭素固定能も増加します。
自然に藻食性生物を制御するなら、生態系の食物連鎖の回復が重要です。
つまり生態系における高次捕食者の回復が重要だとおもっています。
ところが、高次捕食者を考えずに保護すると、海藻は増えますが、炭素固定能は再び減少します。
これは、先程のスライドにもあった生態ピラミッドがポイントです。
ピラミッドの下級に存在知るバイオマスが多いときこそ、生態系に多くの炭素が滞留するからです。
下級クラスの生物がへると、海藻は確かに増えるが、その分のバイオマスが減るので、生態系そのもに滞留する炭素は少なくなります。
研究室では、この図で描いた仮説を様々な視点から検証しています。

参考文献：Atwood et al. (2015)

Nature-based climate solutions

Nature-based climate solutions (i.e., preserving and enhancing carbon removal and storage by ecosystems) can contribute to reducing the effects of global warming (Matthews et al. 2022).

Seaweed aquaculture

Seaweed production (Duarte, Bruhn, and Krause-Jensen 2021)

Seaweed aquaculture is growing at 6.2% yr^-1
2050 projection
- 5.5 Tg CO₂ yr^-1
- 187 Mt FW yr^-1 food demand (5.3 g_dw person^-1 day^-1 Japan standard)
- 160 Mt FW yr^-1 animal feed (1 % of feed contributed by seaweed)
Blue carbon potential varies with species and location (Sato et al. 2022).

さらに、海藻養殖における炭素固定能力の評価も研究しています。
20年前から、Carlos Duarte を中心に、海藻藻場の炭素固定能の評価が進んでいます。
とくに、欧米ではコンブ目のケルプの養殖に関する研究は進んでいます。
それにしても、アジアではコンブ、ワカメやミリン科のキリンサイなどが養殖されています。
世界的には、海藻養殖業は年間 6.2% あたり成長していると報告されています。
さらに、2050年には、海藻養殖において、二酸化炭素をおよそ 5.5 兆グラム固定すると予測されています。
ところが、研究室では養殖に使用される種と場所は、二酸化炭素固定能に大きく関わっていると考えています。
さらに、先程紹介したスライドにあったが、海藻が排出する有機炭素と炭酸カルシウムの効果は現在の見積もりに含まれていない。
つまり、海藻養殖の炭素固定能は生産量のデータだけに頼りと過小評価になると考えています。

Case study: Northern Ireland

Saccharina latissima (カラフトコンブ) (Dolliver and O’Connor 2022).

Net primary production (NPP) of at most 4000 g C m^-1 cultivation rope (100 m).
Average harvested biomass contains about 15.8 g C m^-2 cultivation area.
41% of NPP lost to blade fall-off (detached from cultivation rope)
- 4% (2 kg C / longline) sequestered in continental sediments
- 10% (5.4 kg C / longline) sequestered in deep sea
43% of NPP lost to exudation (DOC)
0.2% of NPP lost to blade erosion (POC)
Sequester potential of 120 g C / m

Case study: Northern Ireland

Saccharina latissima (カラフトコンブ) (Dolliver and O’Connor 2022).

Average harvested kelp biomass contains about 15.8 g C m^-2 cultivation rope (Dolliver and O’Connor 2022).
Wakame（ワカメ）harvested C was at most 14.1 g C m^-2 (Sato et al. 2022).
Mozuku（オキナワモズク） harvested C was 3.7 g C m^-2 (Sato et al. 2022).
Hirota Bay wakame farm (229 ha) captures 32 tons C yr^-1 (Sato et al. 2022).
Bise Point mozuku farm (24.7 ha ) captures 0.9 tons C yr^-1 (Sato et al. 2022).

Criticisms

Blue Carbon estimates are uncertain and unreliable (Williamson and Gattuso 2022). Seagrass ecosystems range from 6.9 to 521 mg C mg^-2 day^-1
Seaweed carbon sequestration base on net ecosystem production of -4 mmol C m^-2 day^-1 (Gallagher, Shelamoff, and Layton 2022)
CO₂ emitted during calcification exceed sequestration (Van Dam et al. 2021).
Sinking seaweed into the deep ocean has unknown environmental and social risk (Ricart et al. 2022).
Carbon accounting must include carbon flow analysis (Hurd et al. 2022)
The flux of carbon after seaweed consumption is unknown.

海藻におけるブルーカーボンの問題点

海藻に対するブルーカーボン能を正確に図った事例はない。
そもそも、藻場が吸収した炭素の行方は不明確です。
それにしても、海草群落に対する推定量にばらつきがある。
純生産量を基準とした推定は -4 mmol C m^-2 yr^-1 であると指摘されている。しかしこの推定に使用したデータ数も少ない。
アマモ場において、生物における石灰化の二酸化炭素放出は炭素固定能を超えているとも指摘されているが、一例の研究のため、情報は不十分。それにしても、石灰化によって一部の炭素を固定している。この点についての研究が必要。
深海にケルプを沈める計画もあるが、生態系や社会における影響評価は必要。
ブルーカーボンの評価は炭素シンクとソースの他に炭素の移動経路の情報も重要であると指摘されている。
食用海藻の消費後の炭素フラックスは不明である。

What is Blue Carbon?

Carbon captured by the marine ecosystem.
Carbon in the marine ecosystem exists in the form of
- Algae and plant biomass
- Microbial biomass
- Animal biomass
- CaCO₃, CO₂, HCO₃, and CO₃
Blue Carbon is temporary and will only delay the effects of global warming if we continue to use fossil fuels.

Definitions from an ecosystem perspective

Anthropogenic greenhouse gas emissions

These are emissions that are caused by changes to the ecosystem due to human activity. For example, the loss of forests can lead to the release of carbon trapped in the sediments. These are emissions that could be prevented by appropriate management action.

Blue carbon

The carbon sequestered and stored in coastal and oceanic ecosystems.

Carbon cycle

The flow of carbon through the biosphere, lithosphere, and atomosphere. Processes drive carbon flow are photosynthesis, calcification, dissolution, metabolic respiration, and decomposition.

Carbon flux

The transfer of carbon from one reservoir to another.

Carbon reservoir

A part of the climate system, excluding the atmosphere, that can store, accumulate, and release carbon, greenhouse gases, or a precursor. Also known as a carbon pool. The quantity stored in the carbon reservoir is known as the carbon stock.

Carbon sink

A process, activity, or mechanism that removes a greenhouse gas, aerosol, or a precursor from the atmosphere.

Carbon source

A process, activity, or mechanism that releases a greenhouse gas, aerosol, or a precursor into the atmosphere.

Carbon uptake and sequestration

Carbon uptake is the addition of carbon into a carbon reservoir. Also called carbon sequestration. These processes should remove carbon on times0-scales of at least decades, and also should have an impact on atmospheric levels of greenhouse gases.

Greenhouse gases

Natural and anthropogenic gases that absorb and emit radiation that causes the greenhouse effect.

The primary greenhouse gases are:

Water vapor (H₂O)
Carbon dioxide (CO₂)
Nitrous oxide (N₂O)
Methane (CH₄)
Ozone (O₃)

References

A. Muller, Richard, Robert Rohde, Robert Jacobsen, Elizabeth Muller, and Charlotte Wickham. 2013. “A New Estimate of the Average Earth Surface Land Temperature Spanning 1753 to 2011.” Geoinformatics & Geostatistics: An Overview 01 (01). https://doi.org/10.4172/2327-4581.1000101.

Arrhenius, Svante. 1896. “XXXI.On the Influence of Carbonic Acid in the Air Upon the Temperature of the Ground.” The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 41 (251): 237–76. https://doi.org/10.1080/14786449608620846.

Atwood, Trisha B., Rod M. Connolly, Euan G. Ritchie, Catherine E. Lovelock, Michael R. Heithaus, Graeme C. Hays, James W. Fourqurean, and Peter I. Macreadie. 2015. “Predators Help Protect Carbon Stocks in Blue Carbon Ecosystems.” Nature Climate Change 5 (12): 1038–45. https://doi.org/10.1038/nclimate2763.

Callendar, G. S. 1938. “The Artificial Production of Carbon Dioxide and Its Influence on Temperature.” Quarterly Journal of the Royal Meteorological Society 64 (275): 223–40. https://doi.org/10.1002/qj.49706427503.

“Continental-Scale Temperature Variability During the Past Two Millennia.” 2013. Nature Geoscience 6 (5): 339–46. https://doi.org/10.1038/ngeo1797.

Davison, P. C., D. M. Checkley, J. A. Koslow, and J. Barlow. 2013. “Carbon Export Mediated by Mesopelagic Fishes in the Northeast Pacific Ocean.” Progress in Oceanography 116 (September): 14–30. https://doi.org/10.1016/j.pocean.2013.05.013.

Dolliver, Jessie, and Nessa E. O’Connor. 2022. “Estimating Growth, Loss and Potential Carbon Sequestration of Farmed Kelp: A Case Study of Saccharina Latissima at Strangford Lough, Northern Ireland.” Applied Phycology 3 (1): 324–39. https://doi.org/10.1080/26388081.2022.2081934.

Duarte, Carlos M., Annette Bruhn, and Dorte Krause-Jensen. 2021. “A Seaweed Aquaculture Imperative to Meet Global Sustainability Targets.” Nature Sustainability 5 (3): 185–93. https://doi.org/10.1038/s41893-021-00773-9.

Duarte de Paula Costa, Micheli, and Peter I. Macreadie. 2022. “The Evolution of Blue Carbon Science.” Wetlands 42 (November): 109. https://doi.org/10.1007/s13157-022-01628-5.

Easterling, David R., Thomas R. Karl, Kevin P. Gallo, David A. Robinson, Kevin E. Trenberth, and Aiguo Dai. 2000. “Observed Climate Variability and Change of Relevance to the Biosphere.” Journal of Geophysical Research: Atmospheres 105 (D15): 20101–14. https://doi.org/10.1029/2000jd900166.

Fourier, Joseph. 1824. “Remarques générales sur les températures du globe terrestre et des espaces planétaires.” Annales de Chemie et de Physique 27: 136–67.

———. 1827. “Mémoire sur les températures du globe terrestre dt des espaces planétaires.” Mémoires de l’Académie Royale des Sciences 7: 569–604.

Frigstad, Helene, Hege Gundersen, Guri S. Andersen, Gunhild Borgersen, Kristina Ø. Kvile, Dorte Krause-Jensen, Christoffer Boström, et al. 2021. Blue Carbon Climate Adaptation, CO2 Uptake and Sequestration of Carbon in Nordic Blue Forests Results from the Nordic Blue Carbon Project. Nordic Council of Ministers. https://doi.org/10.6027/temanord2020-541.

Gallagher, John Barry, Victor Shelamoff, and Cayne Layton. 2022. “Seaweed Ecosystems May Not Mitigate CO2 Emissions.” Edited by Ivan Rodil. ICES Journal of Marine Science 79 (3): 585–92. https://doi.org/10.1093/icesjms/fsac011.

Hansen, James, Andrew Lacis, Reto Ruedy, and Makiko Sato. 1992. “Potential Climate Impact of Mount Pinatubo Eruption.” Geophysical Research Letters 19 (2): 215–18. https://doi.org/10.1029/91gl02788.

Hansen, J., D. Johnson, A. Lacis, S. Lebedeff, P. Lee, D. Rind, and G. Russell. 1981. “Climate Impact of Increasing Atmospheric Carbon Dioxide.” Science 213 (4511): 957–66. https://doi.org/10.1126/science.213.4511.957.

House, Kurt Zenz, Christopher H. House, Daniel P. Schrag, and Michael J. Aziz. 2007. “Electrochemical Acceleration of Chemical Weathering as an Energetically Feasible Approach to Mitigating Anthropogenic Climate Change.” Environmental Science & Technology 41 (24): 8464–70. https://doi.org/10.1021/es0701816.

Hurd, Catriona L., Cliff S. Law, Lennart T. Bach, Damon Britton, Mark Hovenden, Ellie R. Paine, John A. Raven, Veronica Tamsitt, and Philip W. Boyd. 2022. “Forensic Carbon Accounting: Assessing the Role of Seaweeds for Carbon Sequestration.” Journal of Phycology 58 (3): 347–63. https://doi.org/10.1111/jpy.13249.

Jones, P. D., T. M. L. Wigley, and P. B. Wright. 1986. “Global Temperature Variations Between 1861 and 1984.” Nature 322 (6078): 430–34. https://doi.org/10.1038/322430a0.

Keeling, C. D., J. F. S. Chin, and T. P. Whorf. 1996. “Increased Activity of Northern Vegetation Inferred from Atmospheric CO2 Measurements.” Nature 382 (6587): 146–49. https://doi.org/10.1038/382146a0.

Keeling, C. D., Piper S. C., Bacastow R. B., M. Whalen, Whorf T. P., Heimann M., and H. A. Meijer. 2001. “Exchanges of Atmospheric CO₂ and ¹³CO₂ with the Terrestrial Biosphere and Oceans from 1978 to 2000.” In I. Global Aspects, SIO Reference Series, No. 01-06, 88. San Diego, USA: Scripps Instituion of Oceanography. https://scrippsco2.ucsd.edu/data/atmospheric_co2/primary_mlo_co2_record.html.

Keeling, Charles D. 1960. “The Concentration and Isotopic Abundances of Carbon Dioxide in the Atmosphere.” Tellus 12 (2): 200–203. https://doi.org/10.1111/j.2153-3490.1960.tb01300.x.

Kheshgi, Haroon S. 1995. “Sequestering Atmospheric Carbon Dioxide by Increasing Ocean Alkalinity.” Energy 20 (9): 915–22. https://doi.org/10.1016/0360-5442(95)00035-f.

Lavery, T. J., B. Roudnew, L. Seuront, J. G. Mitchell, and J. Middleton. 2012. “Can Whales Mix the Ocean?” http://dx.doi.org/10.5194/bgd-9-8387-2012.

Lavery, Trish J., Ben Roudnew, Peter Gill, Justin Seymour, Laurent Seuront, Genevieve Johnson, James G. Mitchell, and Victor Smetacek. 2010. “Iron Defecation by Sperm Whales Stimulates Carbon Export in the Southern Ocean.” Proceedings of the Royal Society B: Biological Sciences 277 (1699): 3527–31. https://doi.org/10.1098/rspb.2010.0863.

Levitus, Sydney, John I. Antonov, Timothy P. Boyer, and Cathy Stephens. 2000. “Warming of the World Ocean.” Science 287 (5461): 2225–29. https://doi.org/10.1126/science.287.5461.2225.

Mann, Michael E., Raymond S. Bradley, and Malcolm K. Hughes. 1999. “Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations.” Geophysical Research Letters 26 (6): 759–62. https://doi.org/10.1029/1999gl900070.

Martin, Summer L., Lisa T. Ballance, and Theodore Groves. 2016. “An Ecosystem Services Perspective for the Oceanic Eastern Tropical Pacific: Commercial Fisheries, Carbon Storage, Recreational Fishing, and Biodiversity.” Frontiers in Marine Science 3 (April). https://doi.org/10.3389/fmars.2016.00050.

Matthews, H. Damon, Kirsten Zickfeld, Mitchell Dickau, Alexander J. MacIsaac, Sabine Mathesius, Claude-Michel Nzotungicimpaye, and Amy Luers. 2022. “Temporary Nature-Based Carbon Removal Can Lower Peak Warming in a Well-Below 2°C Scenario.” Communications Earth & Environment 3 (1). https://doi.org/10.1038/s43247-022-00391-z.

Menzel, Annette, and Peter Fabian. 1999. “Growing Season Extended in Europe.” Nature 397 (6721): 659–59. https://doi.org/10.1038/17709.

Mitchell, J. Murray. 1961. “RECENT SECULAR CHANGES OF GLOBAL TEMPERATURE.” Annals of the New York Academy of Sciences 95 (1): 235–50. https://doi.org/10.1111/j.1749-6632.1961.tb50036.x.

National Research Council. 2000. Reconciling Observations of Global Temperature Change. National Academies Press. https://doi.org/10.17226/9755.

Ortega, Alejandra, Nathan R. Geraldi, Intikhab Alam, Allan A. Kamau, Silvia G. Acinas, Ramiro Logares, Josep M. Gasol, Ramon Massana, Dorte Krause-Jensen, and Carlos M. Duarte. 2019. “Important Contribution of Macroalgae to Oceanic Carbon Sequestration.” Nature Geoscience 12 (9): 748–54. https://doi.org/10.1038/s41561-019-0421-8.

Ortega, Alejandra, Nathan R. Geraldi, and Carlos M. Duarte. 2020. “Environmental DNA Identifies Marine Macrophyte Contributions to Blue Carbon Sediments.” Limnology and Oceanography 65 (12): 3139–49. https://doi.org/10.1002/lno.11579.

Pedersen, MF, K Filbee-Dexter, NL Frisk, Z Sárossy, and T Wernberg. 2021. “Carbon Sequestration Potential Increased by Incomplete Anaerobic Decomposition of Kelp Detritus.” Marine Ecology Progress Series 660 (February): 53–67. https://doi.org/10.3354/meps13613.

Pershing, Andrew J., Line B. Christensen, Nicholas R. Record, Graham D. Sherwood, and Peter B. Stetson. 2010. “The Impact of Whaling on the Ocean Carbon Cycle: Why Bigger Was Better.” Edited by Stuart Humphries. PLoS ONE 5 (8): e12444. https://doi.org/10.1371/journal.pone.0012444.

Renforth, Phil, and Gideon Henderson. 2017. “Assessing Ocean Alkalinity for Carbon Sequestration.” Reviews of Geophysics 55 (3): 636–74. https://doi.org/10.1002/2016rg000533.

Revelle, Roger, and Hans E. Suess. 1957. “Carbon Dioxide Exchange Between Atmosphere and Ocean and the Question of an Increase of Atmospheric CO₂during the Past Decades.” Tellus 9 (1): 18–27. https://doi.org/10.1111/j.2153-3490.1957.tb01849.x.

Ricart, Aurora M, Dorte Krause-Jensen, Kasper Hancke, Nichole N Price, Pere Masqué, and Carlos M Duarte. 2022. “Sinking Seaweed in the Deep Ocean for Carbon Neutrality Is Ahead of Science and Beyond the Ethics.” Environmental Research Letters 17 (8): 081003. https://doi.org/10.1088/1748-9326/ac82ff.

Roman, Joe, James A Estes, Lyne Morissette, Craig Smith, Daniel Costa, James McCarthy, JB Nation, Stephen Nicol, Andrew Pershing, and Victor Smetacek. 2014. “Whales as Marine Ecosystem Engineers.” Frontiers in Ecology and the Environment 12 (7): 377–85. https://doi.org/10.1890/130220.

Saba, Grace K., and Deborah K. Steinberg. 2012. “Abundance, Composition and Sinking Rates of Fish Fecal Pellets in the Santa Barbara Channel.” Scientific Reports 2 (1). https://doi.org/10.1038/srep00716.

Santer, B. D., T. M. L. Wigley, G. A. Meehl, M. F. Wehner, C. Mears, M. Schabel, F. J. Wentz, et al. 2003. “Influence of Satellite Data Uncertainties on the Detection of Externally Forced Climate Change.” Science 300 (5623): 1280–84. https://doi.org/10.1126/science.1082393.

Sato, Yoichi, Gregory N. Nishihara, Atsuko Tanaka, Dominic F. C. Belleza, Azusa Kawate, Yukio Inoue, Kenjiro Hinode, et al. 2022. “Variability in the Net Ecosystem Productivity (NEP) of Seaweed Farms.” Frontiers in Marine Science 9 (May). https://doi.org/10.3389/fmars.2022.861932.

Sharifian, R., L. Boer, R. M. Wagterveld, and D. A. Vermaas. 2022. “Oceanic Carbon Capture Through Electrochemically Induced in Situ Carbonate Mineralization Using Bipolar Membrane.” Chemical Engineering Journal 438 (June): 135326. https://doi.org/10.1016/j.cej.2022.135326.

Suess, Hans E. 1955. “Radiocarbon Concentration in Modern Wood.” Science 122 (3166): 415–17. https://doi.org/10.1126/science.122.3166.415.b.

Trevathan-Tackett, Stacey M., Jeffrey Kelleway, Peter I. Macreadie, John Beardall, Peter Ralph, and Alecia Bellgrove. 2015. “Comparison of Marine Macrophytes for Their Contributions to Blue Carbon Sequestration.” Ecology 96 (11): 3043–57. https://doi.org/10.1890/15-0149.1.

Tyndall, John. 1861. “I. The Bakerian Lecture.On the Absorption and Radiation of Heat by Gases and Vapours, and on the Physical Connexion of Radiation, Absorption, and Conduction.” Philosophical Transactions of the Royal Society of London 151 (December): 1–36. https://doi.org/10.1098/rstl.1861.0001.

Van Dam, Bryce R., Mary A. Zeller, Christian Lopes, Ashley R. Smyth, Michael E. Böttcher, Christopher L. Osburn, Tristan Zimmerman, Daniel Pröfrock, James W. Fourqurean, and Helmuth Thomas. 2021. “Calcification-Driven CO ₂ Emissions Exceed “Blue Carbon” Sequestration in a Carbonate Seagrass Meadow.” Science Advances 7 (51). https://doi.org/10.1126/sciadv.abj1372.

Watanabe, Kenta, Goro Yoshida, Masakazu Hori, Yu Umezawa, Hirotada Moki, and Tomohiro Kuwae. 2020. “Macroalgal Metabolism and Lateral Carbon Flows Can Create Significant Carbon Sinks.” Biogeosciences 17 (9): 2425–40. https://doi.org/10.5194/bg-17-2425-2020.

Wigley, T. M. L., and P. D. Jones. 1981. “Detecting CO2-Induced Climatic Change.” Nature 292 (5820): 205–8. https://doi.org/10.1038/292205a0.

Williamson, Phillip, and Jean-Pierre Gattuso. 2022. “Carbon Removal Using Coastal Blue Carbon Ecosystems Is Uncertain and Unreliable, with Questionable Climatic Cost-Effectiveness.” Frontiers in Climate 4 (July). https://doi.org/10.3389/fclim.2022.853666.

Wilmers, Christopher C, James A Estes, Matthew Edwards, Kristin L Laidre, and Brenda Konar. 2012. “Do Trophic Cascades Affect the Storage and Flux of Atmospheric Carbon? An Analysis of Sea Otters and Kelp Forests.” Frontiers in Ecology and the Environment 10 (8): 409–15. https://doi.org/10.1890/110176.

Wilson, R. W., F. J. Millero, J. R. Taylor, P. J. Walsh, V. Christensen, S. Jennings, and M. Grosell. 2009. “Contribution of Fish to the Marine Inorganic Carbon Cycle.” Science 323 (5912): 359–62. https://doi.org/10.1126/science.1157972.

Yoshikawa, Takashi, Ichiro Takeuchi, and Ken Furuya. 2001. “Active Erosion of Undaria Pinnatifida Suringar (Laminariales, Phaeophyceae) Mass-Cultured in Otsuchi Bay in Northeastern Japan.” Journal of Experimental Marine Biology and Ecology 266 (1): 51–65. https://doi.org/10.1016/s0022-0981(01)00346-x.

Zaborska, Agata, Maria Włodarska-Kowalczuk, Joanna Legeżyńska, Emilia Jankowska, Aleksandra Winogradow, and Kajetan Deja. 2018. “Sedimentary Organic Matter Sources, Benthic Consumption and Burial in West Spitsbergen Fjords Signs of Maturing of Arctic Fjordic Systems?” Journal of Marine Systems 180 (April): 112–23. https://doi.org/10.1016/j.jmarsys.2016.11.005.

藻場のブルーカーボンの現在と課題